1.Diaphragm contracts and drops
2.Lung volume gets larger, creating negative pressure difference
3.Air rushes in

1.Air rushes in
2.Diaphragm contracts
3.Lung volume gets larger, creating a negative pressure difference

1.Lung volume decreases, creating a positive pressure difference
2.Air rushes out
3.Diaphragm relaxes and rises

1.Diaphragm relaxes and rises
2.Lung volume decreases, creating a positive pressure difference
3.Air rushes out

Low concentration ----> High concentration

High concentration ----> Low concentration

Heart

Lungs

Alveoli

Blood stream

To allow blood to transfer across

To allow gas to transfer across

To allow lymph to transfer across

So lots of gas can pass through

So lots of blood can pass through

So lots of lymph can pass through